Low cost micro OLED structure and method

ABSTRACT

A method of manufacturing a display system includes forming a display element having a display active area over a silicon backplane, forming a display driver integrated circuit (DDIC), and bonding the display element to the display driver integrated circuit (DDIC). The display active area may include a light emitting diode such as an organic light emitting diode (OLED). Separately forming the display and the display circuitry may simplify formation of the OLED and allow for a higher density control interface between the display and the DDIC.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority under 35 U.S.C. § 119(e)of U.S. Provisional Application No. 62/808,642, filed Feb. 21, 2019, thecontents of which are incorporated herein by reference in theirentirety.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate a number of exemplary embodimentsand are a part of the specification. Together with the followingdescription, these drawings demonstrate and explain various principlesof the instant disclosure.

FIG. 1 is a diagram of a head-mounted display (HMD) that includes anear-eye display (NED) according to some embodiments.

FIG. 2 is a cross-section view of the HMD illustrated in FIG. 1according to some embodiments.

FIG. 3 illustrates an isometric view of a waveguide display inaccordance with various embodiments.

FIG. 4 depicts a simplified OLED structure according to someembodiments.

FIG. 5 is a schematic view of an OLED display according to someembodiments.

FIG. 6 is a schematic view of a micro-OLED package according to certainembodiments.

FIG. 7 depicts a micro-OLED package with various control circuitelements separate from a silicon backplane according to someembodiments.

FIG. 8 shows a micro-OLED package with various control circuit elements,including a source driver, separate from a silicon backplane accordingto certain embodiments.

FIG. 9 is an illustration of an exemplary artificial-reality headbandthat may be used in connection with embodiments of this disclosure.

FIG. 10 is an illustration of exemplary augmented-reality glasses thatmay be used in connection with embodiments of this disclosure.

FIG. 11 is an illustration of an exemplary virtual-reality headset thatmay be used in connection with embodiments of this disclosure.

Throughout the drawings, identical reference characters and descriptionsindicate similar, but not necessarily identical, elements. While theexemplary embodiments described herein are susceptible to variousmodifications and alternative forms, specific embodiments have beenshown by way of example in the drawings and will be described in detailherein. However, the exemplary embodiments described herein are notintended to be limited to the particular forms disclosed. Rather, theinstant disclosure covers all modifications, equivalents, andalternatives falling within the scope of the appended claims.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Optical displays are ubiquitous in emerging technologies, includingwearable devices, smart phones, tablets, laptops, desktop computers, andother display systems. Many display systems used in such technologiesare based on light emitting diodes (LEDs), including organic lightemitting diodes (OLEDs). The present disclosure relates generally todisplay systems and, more specifically, to methods of manufacturingorganic light emitting diode (OLED)-based displays, including microOLED-based displays.

An LED-based display system can be manufactured by assembling an arrayof individual LED display elements. One or more LED display elements canbe grouped to form pixels. The display system may include controlcircuitry to generate and distribute control signals to control eachpixel to project an image. The display system may further include abackplane to provide structural support for the LED display elements andto provide electrical connections to transmit the control signals to theLED display devices. Integration of the LED display elements with thebackplane and with additional circuits, such as display driver circuits,can affect pixel-level interconnects, including the size and density ofa pixel array, and ultimately the quality and the performance of thedisplay system.

Notwithstanding recent developments, it would be advantageous to provideimproved integration and packaging schemes for the economicalmanufacture of large area, performance-enhanced light emittingdiode-based displays. In many comparative OLED architectures, forinstance, it may be conventional to integrate the driving electronicsonto the backplane, which may beneficially simplify the formation ofback end interconnections. However, the foregoing approach may relegatea majority of the display backplane to a display driver integratedcircuit (DDIC), which may unduly increase the complexity of circuitdesign and the associated cost of manufacture.

In view of the foregoing, Applicants have shown that an improved displayarchitecture may be achieved by forming a plurality of pixel transistorson the backplane, while locating a majority of the driver electronics,including the source driver, on a discrete DDIC. In turn, the DDIC maybe bonded to the backplane and the attendant transistor circuitry using,for example, a chip-on-flex process in conjunction with a high pitchdensity (e.g., multiplexer-based) interconnect.

As disclosed herein, a method of manufacturing an LED-based display mayinclude separately forming (i) a display element, including a displayactive area disposed over a silicon backplane, and (ii) a display driverintegrated circuit (DDIC). Once formed, the display element may bebonded to the DDIC using a chip-on-flex (COF) bonding process, forexample. In some embodiments, individual LED display elements mayinclude organic light emitting diodes (OLEDs). The disclosed methods andstructures may be used to manufacture low cost, high resolution displayshaving a commercially-relevant form factor (e.g., having one or morelateral dimensions greater than approximately 1.3 inches).

Particularly for higher density displays, by forming the display and theDDIC separately, co-integration challenges may be circumvented such thatthe overall manufacturing process may be more economical. For instance,and in accordance with various embodiments, the DDIC may be formed at an80 nm process node, e.g., using conventional CMOS technology, while thedisplay package, including the display elements and the supportingbackplane, may be assembled using a less restrictive, lower cost 0.5-1.0micron process.

In addition, the higher carrier mobility of a single crystalsemiconductor backplane (i.e., relative to glass, polymer, or evenpolycrystalline semiconductors) and the attendant improvements in deviceoperating speed may enable the creation of an increasingly complex dataselection interface between the display elements and the display drivercircuitry. A higher density data selection interface may enable higherpixel densities within the display active area and higher qualityimages. For example, the data selection interface may include one ormore multiplexers having a ratio of input channels to an output channelof at least 4, e.g., 4, 8, 12, 16, 18, 20, or 24, although still higherdensity multiplexers are contemplated. According to some embodiments,the instant display systems may include microLEDs as well asmicro-OLEDs, and may be incorporated into a variety of form factors,such as wearable near-eye displays (NEDs).

According to various embodiments, a method includes forming a displayelement including an LED-containing display active area over a siliconbackplane, forming a display driver integrated circuit (DDIC), andbonding the display element to the display driver integrated circuit. Insome embodiments, in addition to pixel transistors, a gate driver (gateline driving circuit) may be incorporated onto the backplane, whereas asource driver (data line driving circuit) may be incorporated onto theDDIC.

The display element may be electrically connected to the display driverintegrated circuit via a multiplexer. In some embodiments, the displayelement may be attached to a flexible substrate and the display activearea electrically connected to the display driver integrated circuit bya wire bond. The foregoing architecture may enable large area displays,including displays having at least one lateral dimension greater thanapproximately 1.5 inches.

According to further embodiments, a display system may include a displayelement having an LED-containing (e.g., OLED-containing ormicro-OLED-containing) display active area disposed over a siliconbackplane, a display driver integrated circuit (DDIC) attached to thedisplay element and electrically connected with the display active area,and a multiplexer disposed between the display element and the displaydriver integrated circuit. In some embodiments, the display driverintegrated circuit may be formed on a flexible substrate.

Features from any of the above-mentioned embodiments may be used incombination with one another according to the general principlesdescribed herein. These and other embodiments, features, and advantageswill be more fully understood upon reading the following detaileddescription in conjunction with the accompanying drawings and claims.

In certain embodiments, a method of manufacturing an LED-based displayincludes forming a display element including a display active areadisposed over a silicon backplane, forming a display driver integratedcircuit (DDIC), and bonding the display element to the display driverintegrated circuit. Thus, the display and the DDIC may be manufacturedseparately and then joined, i.e., physically bonded and electricallyinterconnected. Because design rules for the display and the DDIC maynot be co-extensive, separate manufacturing paradigms may be used toimprove the economics of the overall process. For instance, separatemanufacture of the display and the DDIC may decrease the total number ofrequired critical masks and/or increase manufacturing flexibility in oneor both sub-processes.

In addition, by using a silicon backplane to form the display, thegreater carrier mobility and the associated improvements in operatingspeed may enable the formation of an increasingly complex data selectioninterface (i.e., multiplexer interface) between the display element(s)and the display driver circuitry. Higher density multiplexers supportthe realization of higher pixel densities and higher quality images. Forinstance, according to some embodiments, a multiplexer may have 4 ormore inputs (e.g., 4, 8, 12, 16, 18, 20, 22, 24 or more inputs) for eachoutput.

As will be appreciated, the LED-based displays described herein mayinclude microLEDs. Moreover, the LED-based displays may include organicLEDs (OLEDS), including micro-OLEDs. The LED-based displays may beincorporated into a variety of devices, such as wearable near-eyedisplays (NEDs).

The following will provide, with reference to FIGS. 1-11, a detaileddescription of LED devices, systems, and methods of manufacture. Thediscussion associated with FIGS. 1-3 relates to an example near-eyedisplay (NED). The discussion associated with FIGS. 4-8 includes adescription of an OLED and an OLED package in accordance with variousembodiments. The discussion associated with FIGS. 9-11 relates tovarious virtual reality platforms that may include a display device asdescribed herein.

FIG. 1 is a diagram of a near-eye-display (NED) 100, in accordance withsome embodiments. The NED 100 may present media to a user. Examples ofmedia that may be presented by the NED 100 include one or more images,video, audio, or some combination thereof. In some embodiments, audiomay be presented via an external device (e.g., speakers and/orheadphones) that receives audio information from the NED 100, a console(not shown), or both, and presents audio data to the user based on theaudio information. The NED 100 is generally configured to operate as avirtual reality (VR) NED. However, in some embodiments, the NED 100 maybe modified to also operate as an augmented reality (AR) NED, a mixedreality (MR) NED, or some combination thereof. For example, in someembodiments, the NED 100 may augment views of a physical, real-worldenvironment with computer-generated elements (e.g., images, video,sound, etc.).

The NED 100 shown in FIG. 1 may include a frame 105 and a display 110.The frame 105 may include one or more optical elements that togetherdisplay media to a user. That is, the display 110 is configured for auser to view the content presented by the NED 100. As discussed below inconjunction with FIG. 2, the display 110 may include at least one sourceassembly to generate image light to present media to an eye of the user.The source assembly may include, e.g., a source, an optics system, orsome combination thereof.

It will be appreciated that FIG. 1 is merely an example of a virtualreality system, and the display systems described herein may beincorporated into further such systems. In some embodiments, FIG. 1 mayalso be referred to as a Head-Mounted-Display (HMD).

FIG. 2 is a cross section 200 of the NED 100 illustrated in FIG. 1, inaccordance with some embodiments of the present disclosure. The crosssection 200 includes at least one display assembly 210, and an exitpupil 230. The exit pupil 230 is a location where the eye 220 may bepositioned when the user wears the NED 100. In some embodiments, theframe 105 may represent a frame of eye-wear glasses. For purposes ofillustration, FIG. 2 shows the cross section 200 associated with asingle eye 220 and a single display assembly 210, but in alternativeembodiments not shown, another display assembly that is separate fromthe display assembly 210 shown in FIG. 2, may provide image light toanother eye 220 of the user.

The display assembly 210, as illustrated in FIG. 2, may be configured todirect the image light to the eye 220 through the exit pupil 230. Thedisplay assembly 210 may be composed of one or more materials (e.g.,plastic, glass, etc.) with one or more refractive indices thateffectively decrease the weight and widen a field of view (hereinafterabbreviated as ‘FOV’) of the NED 100.

In alternate configurations, the NED 100 may include one or more opticalelements (not shown) between the display assembly 210 and the eye 220.The optical elements may act to, by way of various examples, correctaberrations in image light emitted from the display assembly 210,magnify image light emitted from the display assembly 210, perform someother optical adjustment of image light emitted from the displayassembly 210, or combinations thereof. Example optical elements mayinclude an aperture, a Fresnel lens, a convex lens, a concave lens, afilter, or any other suitable optical element that may affect imagelight.

In some embodiments, the display assembly 210 may include a sourceassembly to generate image light to present media to a user's eyes. Thesource assembly may include, e.g., a source, an optics system, or somecombination thereof.

FIG. 3 illustrates an isometric view of a waveguide display 300 inaccordance with some embodiments. In some embodiments, the waveguidedisplay 300 may be a component (e.g., display assembly 210) of NED 100.In alternate embodiments, the waveguide display 300 may constitute apart of some other NED, or other system that directs display image lightto a particular location.

The waveguide display 300 may include a source assembly 310, an outputwaveguide 320, and a controller 330. For purposes of illustration, FIG.3 shows the waveguide display 300 associated with a single eye 220, butin some embodiments, another waveguide display separate (or partiallyseparate) from the waveguide display 300 may provide image light toanother eye of the user. In a partially separate system, for instance,one or more components may be shared between waveguide displays for eacheye.

The source assembly 310 generates image light. The source assembly 310may include a source 340, a light conditioning assembly 360, and ascanning mirror assembly 370. The source assembly 310 may generate andoutput image light 345 to a coupling element 350 of the output waveguide320.

The source 340 may include a source of light that generates at least acoherent or partially coherent image light 345. The source 340 may emitlight in accordance with one or more illumination parameters receivedfrom the controller 330. The source 340 may include one or more sourceelements, including, but not restricted to light emitting diodes, suchas Micro-OLEDs, as described in detail below with reference to FIGS.4-8.

The output waveguide 320 may be configured as an optical waveguide thatoutputs image light to an eye 220 of a user. The output waveguide 320receives the image light 345 through one or more coupling elements 350,and guides the received input image light 345 to one or more decouplingelements 360. In some embodiments, the coupling element 350 couples theimage light 345 from the source assembly 310 into the output waveguide320. The coupling element 350 may be, for example, a diffractiongrating, a holographic grating, some other element that couples theimage light 345 into the output waveguide 320, or some combinationthereof. For example, in embodiments where the coupling element 350 is adiffraction grating, the pitch of the diffraction grating may be chosensuch that total internal reflection occurs, and the image light 345propagates internally toward the decoupling element 360. For example,the pitch of the diffraction grating may be in the range of 300 nm to600 nm.

The decoupling element 360 decouples the total internally reflectedimage light from the output waveguide 320. The decoupling element 360may be, for example, a diffraction grating, a holographic grating, someother element that decouples image light out of the output waveguide320, or some combination thereof. For example, in embodiments where thedecoupling element 360 is a diffraction grating, the pitch of thediffraction grating may be chosen to cause incident image light to exitthe output waveguide 320. An orientation and position of the image lightexiting from the output waveguide 320 may be controlled by changing anorientation and position of the image light 345 entering the couplingelement 350.

The output waveguide 320 may be composed of one or more materials thatfacilitate total internal reflection of the image light 345. The outputwaveguide 320 may be composed of, for example, silicon, plastic, glass,or a polymer, or some combination thereof. The output waveguide 320 mayhave a relatively small form factor such as for use in a head-mounteddisplay. For example, the output waveguide 320 may be approximately 50mm wide along an x-dimension, 30 mm long along a y-dimension, and 0.5-1mm thick along a z-dimension. In some embodiments, the output waveguide320 may be a planar (2D) optical waveguide.

The controller 330 may be used to control the scanning operations of thesource assembly 310. In certain embodiments, the controller 330 maydetermine scanning instructions for the source assembly 310 based atleast on the one or more display instructions. Display instructions mayinclude instructions to render one or more images. In some embodiments,display instructions may include an image file (e.g., bitmap). Thedisplay instructions may be received from, e.g., a console of a virtualreality system (not shown). Scanning instructions may includeinstructions used by the source assembly 310 to generate image light345. The scanning instructions may include, e.g., a type of a source ofimage light (e.g. monochromatic, polychromatic), a scanning rate, anorientation of scanning mirror assembly 370, and/or one or moreillumination parameters, etc. The controller 330 may include acombination of hardware, software, and/or firmware not shown here so asnot to obscure other aspects of the disclosure.

According to some embodiments, source 340 may include a light emittingdiode (LED), such as an organic light emitting diode (OLED). An organiclight-emitting diode (OLED) is a light-emitting diode (LED) having anemissive electroluminescent layer that may include a thin film of anorganic compound that emits light in response to an electric current.The organic layer is typically situated between a pair of conductiveelectrodes. One or both of the electrodes may be transparent.

As will be appreciated, an OLED display can be driven with apassive-matrix (PMOLED) or active-matrix (AMOLED) control scheme. In aPMOLED scheme, each row (and line) in the display may be controlledsequentially, whereas AMOLED control typically uses a thin-filmtransistor backplane to directly access and switch each individual pixelon or off, which allows for higher resolution and larger display areas.

A simplified structure of an OLED according to some embodiments isdepicted in FIG. 4. As shown in an exploded view, OLED 400 may include,from bottom to top, a substrate 410, anode 420, hole injection layer430, hole transport layer 440, emissive layer 450, blocking layer 460,electron transport layer 470, and cathode 480. In some embodiments,substrate (or backplane) 410 may include single crystal orpolycrystalline silicon or other suitable semiconductor (e.g.,germanium).

Anode 420 and cathode 480 may include any suitable conductivematerial(s), such as transparent conductive oxides (TCOs, e.g., indiumtin oxide (ITO), zinc oxide (ZnO), and the like). The anode 420 andcathode 480 are configured to inject holes and electrons, respectively,into the organic layer(s) within emissive layer 450 during operation ofthe device.

The hole injection layer 430, which is disposed over the anode 420,receives holes from the anode 420 and is configured to inject the holesdeeper into the device, while the adjacent hole transport layer 440 maysupport the transport of holes to the emissive layer 450. The emissivelayer 450 converts electrical energy to light. Emissive layer 450 mayinclude one or more organic molecules, or light-emitting fluorescentdyes or dopants, which may be dispersed in a suitable matrix.

Blocking layer 460 may improve device function by confining electrons(charge carriers) to the emissive layer 450. Electron transport layer470 may support the transport of electrons from the cathode 480 to theemissive layer 450.

In some embodiments, the generation of red, green, and blue light (torender full-color images) may include the formation of red, green, andblue OLED sub-pixels in each pixel of the display. Alternatively, theOLED 400 may be adapted to produce white light in each pixel. The whitelight may be passed through a color filter to produce red, green, andblue sub-pixels.

Any suitable deposition process(es) may be used to form OLED 400. Forexample, one or more of the layers constituting the OLED may befabricated using physical vapor deposition (PVD), chemical vapordeposition (CVD), evaporation, spray-coating, spin-coating, atomic layerdeposition (ALD), and the like. In further aspects, OLED 400 may bemanufactured using a thermal evaporator, a sputtering system, printing,stamping, etc.

According to some embodiments, OLED 400 may be a micro-OLED. A“micro-OLED,” according to various examples, may refer to a particulartype of OLED having a small active light emitting area (e.g., less than2,000 μm² in some embodiments, less than 20 μm² or less than 10 μm² inother embodiments). In some embodiments, the emissive surface of themicro-OLED may have a diameter of less than approximately 2 μm. Such amicro-OLED may also have collimated light output, which may increase thebrightness level of light emitted from the small active light emittingarea.

An example OLED device is shown schematically in FIG. 5. According tosome embodiments, OLED device 500 (e.g., micro-OLED chip) may include adisplay active area 530 having an active matrix 532 (such as OLED 400)disposed over a single crystal (e.g., silicon) backplane 520. Thecombined display/backplane architecture, i.e., display element 540 maybe bonded (e.g., at or about interface A) to a display driver integratedcircuit (DDIC) 510. As illustrated, DDIC 510 may include an array ofdriving transistors 512, which may be formed using conventional CMOSprocessing as will be appreciated by those skilled in the art. One ormore display driver integrated circuits may be formed over a singlecrystal (e.g., silicon) substrate.

In some embodiments, the display active area 530 may have at least oneareal dimension (i.e., length or width) greater than approximately 1.3inches, e.g., approximately 1.5, 1.75, 2, 2.25, 2.5, 2.75, or 3 inches,including ranges between any of the foregoing values, although largerarea displays are contemplated.

Silicon backplane 520 may include a single crystal or polycrystallinesilicon layer 523 having a metallization structure 525 for electricallyconnecting the DDIC 510 with the display active area 530. In someembodiments, display active area 530 may further include, from bottom totop, a transparent encapsulation layer 534 disposed over an upperemissive surface 533 of active matrix 532, a color filter 536, and coverglass 538.

According to various embodiments, the display active area 530 andunderlying silicon backplane 520 may be manufactured separately from,and then later bonded to, DDIC 510, which may simplify formation of theOLED active area, including formation of the active matrix 532, colorfilter 536, etc.

According to some embodiments, and with reference to FIG. 6, achip-on-flex (COF) packaging technology may be used to integrate displayelement 540 with DDIC 510, optionally via a data selector (i.e.,multiplexer) array 650 to form a display 600. In certain embodiments,DDIC 510 may be formed on a flexible substrate.

As used herein, the terms “multiplexer” or “data selector” may, in someexamples, refer to a device adapted to combine or select from amongplural analog or digital input signals, which are transmitted to asingle output. Multiplexers may be used to increase the amount of datathat can be communicated within a certain amount of space, time andbandwidth.

As used herein, “chip-on-flex” (COF) may, in some examples, refer to anassembly technology where a microchip or die, such as an OLED chip, isdirectly mounted on and electrically connected to a flexible circuit,such as a direct driver circuit. In a COF assembly, the microchip mayavoid some of the traditional assembly steps used for individual ICpackaging. This may simplify the overall processes of design andmanufacture while improving performance and yield.

In accordance with certain embodiments, COF assembly may includeattaching a die to a flexible substrate, electrically connecting (e.g.,wire bonding) the chip to the flex circuit, and encapsulating the chipand wires, e.g., using an epoxy resin to provide environmentalprotection.

In some embodiments, the adhesive (not shown) used to bond the chip tothe flex substrate may be thermally conductive or thermally insulating.In some embodiments, ultrasonic or thermosonic wire bonding techniquesmay be used to electrically connect the chip to the flex substrate.

Display driver integrated circuits (DDICs), which may also be referredto herein as driver ICs, may receive image data and deliver analogvoltages or currents to activate one or more pixels within the display600. As will be appreciated, driver ICs may include gate drivers andsource drivers. In accordance with various embodiments, a gate drivermay refer to a power amplifier that accepts a low-power input from acontroller IC and produces a high-current drive input for the gate of atransistor, such as an insulated gate bipolar transistor (IGBT) or powermetal-oxide-semiconductor field effect transistor (MOSFET). In someembodiments, a gate driver may be configured to turn on and off selectedtransistors within each pixel cell across a horizontal row of thedisplay area. When the transistors are turned on, a source driver maygenerate voltages that are applied to each pixel cell on that row fordata input. In some embodiments, a source driver may be integrated witha digital-to-analog converter (DAC) for generating analog outputvoltages from digital input data to drive individual pixels.

Referring to FIG. 7, shown is a micro-OLED display package where variouscontrol circuit elements may be removed from the silicon backplane andintegrated into the display package via a discrete DDIC. In theembodiment of FIG. 7, display 700 may include a DDIC 710 coupled, e.g.,via a multiplexer (not shown) to silicon backplane 720. Each of adisplay active area 730, gate driver 750, and source driver 760 may beformed over the silicon backplane 720. The DDIC 710, on the other hand,may include I/O interface 770, MIPI receiver 772, timing controller 774,data processing element 776, and bias and reference voltage elements778.

The MIPI (mobile industry processor interface) receiver 772 may be aMIPI display serial interface (DSO, which may include a high-speedpacket-based interface for delivering video data to the display. Timingcontroller 774 may be configured to receive image data and convert thedata format for the source drivers' input. Timing controller 774 mayalso be configured to generate control signals for the gate and sourcedrivers 750, 760.

According to further embodiments, and with reference to FIG. 8, display800 may include a DDIC 810 coupled, e.g., via a multiplexer (not shown)to silicon backplane 820. Display active area 830 and gate driver 850may be formed over the silicon backplane 820, while source driver 860may be incorporated into the DDIC 810 together with I/O interface 870,MIPI receiver 872, timing controller 874, data processing element 876,and bias and reference voltage elements 878. In certain embodiments,source driver 860 may be formed over a single crystal (e.g., silicon)substrate.

A method of manufacturing a micro-OLED includes separately forming (i) adisplay active area, including an active matrix disposed over a siliconbackplane, and (ii) a display driver integrated circuit (DDIC), whichmay include a source driver. Once formed, the active display may bebonded to the DDIC using a chip-on-flex (COF) bonding process, forexample. The method may be used to manufacture lower cost, higherresolution displays having a commercially-relevant form factor (e.g.,lateral dimensions greater than 1.3 inches). Particularly for higherdensity displays, by forming the display and the DDIC separately,co-integration challenges may be avoided such that the overallmanufacturing process may be more economical. For instance, while theDDIC may be formed at an 80 nm process node using CMOS technology, thedisplay package may be assembled using a 50+ micron process node.Furthermore, in conjunction with the higher operating speeds (higherelectron mobility) afforded by a silicon backplane (i.e., relative to apolymer or glass backplane), decoupling display manufacture from DDICmanufacture may enable the creation of increasingly complex dataselection (multiplexers) at the display-DDIC interface, which supportshigher pixel densities and image quality. Finally, in addition toimplementation for micro-OLEDs, the instant approach may be applied alsoto microLEDs.

EXAMPLE EMBODIMENTS

Example 1: A method includes forming a display element having anLED-containing display active area over a silicon backplane, forming adisplay driver integrated circuit (DDIC), electrically connecting thedisplay active area with the display driver integrated circuit byforming a multiplexer between the display element and the display driverintegrated circuit, and bonding the display element to the displaydriver integrated circuit (DDIC), where the multiplexer includes atleast 4 input channels.

Example 2: The method of Example 1, where forming the display elementincludes forming an organic light emitting diode (OLED) within thedisplay active area.

Example 3: The method of any of Examples 1 and 2, where the organiclight emitting diode includes a micro-OLED.

Example 4: The method of any of Examples 1-3, where the siliconbackplane includes single crystal silicon.

Example 5: The method of any of Examples 1-4, further including formingthe display driver integrated circuit on a flexible substrate.

Example 6: The method of any of Examples 1-5, further including forminga plurality of pixel transistors over the silicon backplane.

Example 7: The method of any of Examples 1-6, further includingattaching the display element to a flexible substrate, and electricallyconnecting the display active area to the display driver integratedcircuit.

Example 8: The method of Example 7, where electrically connecting thedisplay active area to the display driver integrated circuit includeswire bonding.

Example 9: The method of any of Examples 1-8, further including forminga gate driver over the silicon backplane.

Example 10: The method of any of Examples 1-9, further including forminga source driver within the display driver integrated circuit.

Example 11: A display system includes (a) a display element having anLED-containing display active area disposed over a silicon backplane,(b) a display driver integrated circuit (DDIC) attached to the displayelement and electrically connected with the display active area, and (c)a multiplexer disposed between the display element and the displaydriver integrated circuit, where the multiplexer includes at least 4input channels.

Example 12: The display system of Example 11, where the display activearea includes a micro-OLED.

Example 13: The display system of any of Examples 11 and 12, where thesilicon backplane includes single crystal silicon.

Example 14: The display system of any of Examples 11-13, where thedisplay driver integrated circuit is disposed on a flexible substrate.

Example 15: The display system of any of Examples 11-14, where thedisplay active area is electrically connected to the display driverintegrated circuit via a wire bond.

Example 16: The display system of any of Examples 11-15, where thedisplay driver integrated circuit includes a source driver.

Example 17: A device includes (a) a display element having a displayactive area disposed over a single crystal semiconductor backplane, and(b) a display driver integrated circuit (DDIC) bonded to the displayelement, where the display active area includes a micro-OLED and thedisplay driver integrated circuit includes a source driver.

Example 18: The device of Example 17, further including a plurality ofpixel transistors disposed over the backplane.

Example 19: The device of any of Examples 17 and 18, further including amultiplexer communicatively coupling the display element to the displaydriver integrated circuit.

Example 20: The device of any of Examples 17-19, where the semiconductorbackplane includes single crystal silicon.

Embodiments of the present disclosure may include or be implemented inconjunction with various types of artificial reality systems. Artificialreality is a form of reality that has been adjusted in some mannerbefore presentation to a user, which may include, e.g., a virtualreality, an augmented reality, a mixed reality, a hybrid reality, orsome combination and/or derivative thereof. Artificial-reality contentmay include completely generated content or generated content combinedwith captured (e.g., real-world) content. The artificial-reality contentmay include video, audio, haptic feedback, or some combination thereof,any of which may be presented in a single channel or in multiplechannels (such as stereo video that produces a three-dimensional effectto the viewer). Additionally, in some embodiments, artificial realitymay also be associated with applications, products, accessories,services, or some combination thereof, that are used to, e.g., createcontent in an artificial reality and/or are otherwise used in (e.g., toperform activities in) an artificial reality.

Artificial-reality systems may be implemented in a variety of differentform factors and configurations. Some artificial reality systems may bedesigned to work without near-eye displays (NEDs), an example of whichis augmented-reality system 900 in FIG. 9. Other artificial realitysystems may include a NED that also provides visibility into the realworld (e.g., augmented-reality system 1000 in FIG. 10) or that visuallyimmerses a user in an artificial reality (e.g., virtual-reality system1100 in FIG. 11). While some artificial-reality devices may beself-contained systems, other artificial-reality devices may communicateand/or coordinate with external devices to provide an artificial-realityexperience to a user. Examples of such external devices include handheldcontrollers, mobile devices, desktop computers, devices worn by a user,devices worn by one or more other users, and/or any other suitableexternal system.

Turning to FIG. 9, augmented-reality system 900 generally represents awearable device dimensioned to fit about a body part (e.g., a head) of auser. As shown in FIG. 9, system 900 may include a frame 902 and acamera assembly 904 that is coupled to frame 902 and configured togather information about a local environment by observing the localenvironment. Augmented-reality system 900 may also include one or moreaudio devices, such as output audio transducers 908(A) and 908(B) andinput audio transducers 910. Output audio transducers 908(A) and 908(B)may provide audio feedback and/or content to a user, and input audiotransducers 910 may capture audio in a user's environment.

As shown, augmented-reality system 900 may not necessarily include a NEDpositioned in front of a user's eyes. Augmented-reality systems withoutNEDs may take a variety of forms, such as head bands, hats, hair bands,belts, watches, wrist bands, ankle bands, rings, neckbands, necklaces,chest bands, eyewear frames, and/or any other suitable type or form ofapparatus. While augmented-reality system 900 may not include a NED,augmented-reality system 900 may include other types of screens orvisual feedback devices (e.g., a display screen integrated into a sideof frame 902).

The embodiments discussed in this disclosure may also be implemented inaugmented-reality systems that include one or more NEDs. For example, asshown in FIG. 10, augmented-reality system 1000 may include an eyeweardevice 1002 with a frame 1010 configured to hold a left display device1015(A) and a right display device 1015(B) in front of a user's eyes.Display devices 1015(A) and 1015(B) may act together or independently topresent an image or series of images to a user. While augmented-realitysystem 1000 includes two displays, embodiments of this disclosure may beimplemented in augmented-reality systems with a single NED or more thantwo NEDs.

In some embodiments, augmented-reality system 1000 may include one ormore sensors, such as sensor 1040. Sensor 1040 may generate measurementsignals in response to motion of augmented-reality system 1000 and maybe located on substantially any portion of frame 1010. Sensor 1040 mayrepresent a position sensor, an inertial measurement unit (IMU), a depthcamera assembly, or any combination thereof. In some embodiments,augmented-reality system 1000 may or may not include sensor 1040 or mayinclude more than one sensor. In embodiments in which sensor 1040includes an IMU, the IMU may generate calibration data based onmeasurement signals from sensor 1040. Examples of sensor 1040 mayinclude, without limitation, accelerometers, gyroscopes, magnetometers,other suitable types of sensors that detect motion, sensors used forerror correction of the IMU, or some combination thereof.Augmented-reality system 1000 may also include a microphone array with aplurality of acoustic transducers 1020(A)-1020(J), referred tocollectively as acoustic transducers 1020. Acoustic transducers 1020 maybe transducers that detect air pressure variations induced by soundwaves. Each acoustic transducer 1020 may be configured to detect soundand convert the detected sound into an electronic format (e.g., ananalog or digital format). The microphone array in FIG. 10 may include,for example, ten acoustic transducers: 1020(A) and 1020(B), which may bedesigned to be placed inside a corresponding ear of the user, acoustictransducers 1020(C), 1020(D), 1020(E), 1020(F), 1020(G), and 1020(H),which may be positioned at various locations on frame 1010, and/oracoustic transducers 1020(1) and 1020(J), which may be positioned on acorresponding neckband 1005.

In some embodiments, one or more of acoustic transducers 1020(A)-(J) maybe used as output transducers (e.g., speakers). For example, acoustictransducers 1020(A) and/or 1020(B) may be earbuds or any other suitabletype of headphone or speaker.

The configuration of acoustic transducers 1020 of the microphone arraymay vary. While augmented-reality system 1000 is shown in FIG. 10 ashaving ten acoustic transducers 1020, the number of acoustic transducers1020 may be greater or less than ten. In some embodiments, using highernumbers of acoustic transducers 1020 may increase the amount of audioinformation collected and/or the sensitivity and accuracy of the audioinformation. In contrast, using a lower number of acoustic transducers1020 may decrease the computing power required by controller 1050 toprocess the collected audio information. In addition, the position ofeach acoustic transducer 1020 of the microphone array may vary. Forexample, the position of an acoustic transducer 1020 may include adefined position on the user, a defined coordinate on frame 1010, anorientation associated with each acoustic transducer, or somecombination thereof.

Acoustic transducers 1020(A) and 1020(B) may be positioned on differentparts of the user's ear, such as behind the pinna or within the auricleor fossa. Or, there may be additional acoustic transducers on orsurrounding the ear in addition to acoustic transducers 1020 inside theear canal. Having an acoustic transducer positioned next to an ear canalof a user may enable the microphone array to collect information on howsounds arrive at the ear canal. By positioning at least two of acoustictransducers 1020 on either side of a user's head (e.g., as binauralmicrophones), augmented-reality device 1000 may simulate binauralhearing and capture a 3D stereo sound field around about a user's head.In some embodiments, acoustic transducers 1020(A) and 1020(B) may beconnected to augmented-reality system 1000 via a wired connection 1030,and in other embodiments, acoustic transducers 1020(A) and 1020(B) maybe connected to augmented-reality system 1000 via a wireless connection(e.g., a Bluetooth® connection). In still other embodiments, acoustictransducers 1020(A) and 1020(B) may not be used at all in conjunctionwith augmented-reality system 1000.

Acoustic transducers 1020 on frame 1010 may be positioned along thelength of the temples, across the bridge, above or below display devices1015(A) and 1015(B), or some combination thereof. Acoustic transducers1020 may be oriented such that the microphone array is able to detectsounds in a wide range of directions surrounding the user wearing theaugmented-reality system 1000. In some embodiments, an optimizationprocess may be performed during manufacturing of augmented-realitysystem 1000 to determine relative positioning of each acoustictransducer 1020 in the microphone array.

In some examples, augmented-reality system 1000 may include or beconnected to an external device (e.g., a paired device), such asneckband 1005. Neckband 1005 generally represents any type or form ofpaired device. Thus, the following discussion of neckband 1005 may alsoapply to various other paired devices, such as charging cases, smartwatches, smart phones, wrist bands, other wearable devices, hand-heldcontrollers, tablet computers, laptop computers and other externalcomputing devices, etc.

As shown, neckband 1005 may be coupled to eyewear device 1002 via one ormore connectors. The connectors may be wired or wireless and may includeelectrical and/or non-electrical (e.g., structural) components. In somecases, eyewear device 1002 and neckband 1005 may operate independentlywithout any wired or wireless connection between them. While FIG. 10illustrates the components of eyewear device 1002 and neckband 1005 inexample locations on eyewear device 1002 and neckband 1005, thecomponents may be located elsewhere and/or distributed differently oneyewear device 1002 and/or neckband 1005. In some embodiments, thecomponents of eyewear device 1002 and neckband 1005 may be located onone or more additional peripheral devices paired with eyewear device1002, neckband 1005, or some combination thereof.

Pairing external devices, such as neckband 1005, with augmented-realityeyewear devices may enable the eyewear devices to achieve the formfactor of a pair of glasses while still providing sufficient battery andcomputation power for expanded capabilities. Some or all of the batterypower, computational resources, and/or additional features ofaugmented-reality system 1000 may be provided by a paired device orshared between a paired device and an eyewear device, thus reducing theweight, heat profile, and form factor of the eyewear device overallwhile still retaining desired functionality. For example, neckband 1005may allow components that would otherwise be included on an eyeweardevice to be included in neckband 1005 since users may tolerate aheavier weight load on their shoulders than they would tolerate on theirheads. Neckband 1005 may also have a larger surface area over which todiffuse and disperse heat to the ambient environment. Thus, neckband1005 may allow for greater battery and computation capacity than mightotherwise have been possible on a stand-alone eyewear device. Sinceweight carried in neckband 1005 may be less invasive to a user thanweight carried in eyewear device 1002, a user may tolerate wearing alighter eyewear device and carrying or wearing the paired device forgreater lengths of time than a user would tolerate wearing a heavystandalone eyewear device, thereby enabling users to more fullyincorporate artificial reality environments into their day-to-dayactivities.

Neckband 1005 may be communicatively coupled with eyewear device 1002and/or to other devices. These other devices may provide certainfunctions (e.g., tracking, localizing, depth mapping, processing,storage, etc.) to augmented-reality system 1000. In the embodiment ofFIG. 10, neckband 1005 may include two acoustic transducers (e.g.,1020(1) and 1020(J)) that are part of the microphone array (orpotentially form their own microphone subarray). Neckband 1005 may alsoinclude a controller 1025 and a power source 1035.

Acoustic transducers 1020(1) and 1020(J) of neckband 1005 may beconfigured to detect sound and convert the detected sound into anelectronic format (analog or digital). In the embodiment of FIG. 10,acoustic transducers 1020(1) and 1020(J) may be positioned on neckband1005, thereby increasing the distance between the neckband acoustictransducers 1020(1) and 1020(J) and other acoustic transducers 1020positioned on eyewear device 1002. In some cases, increasing thedistance between acoustic transducers 1020 of the microphone array mayimprove the accuracy of beamforming performed via the microphone array.For example, if a sound is detected by acoustic transducers 1020(C) and1020(D) and the distance between acoustic transducers 1020(C) and1020(D) is greater than, e.g., the distance between acoustic transducers1020(D) and 1020(E), the determined source location of the detectedsound may be more accurate than if the sound had been detected byacoustic transducers 1020(D) and 1020(E).

Controller 1025 of neckband 1005 may process information generated bythe sensors on neckband 1005 and/or augmented-reality system 1000. Forexample, controller 1025 may process information from the microphonearray that describes sounds detected by the microphone array. For eachdetected sound, controller 1025 may perform a direction-of-arrival (DOA)estimation to estimate a direction from which the detected sound arrivedat the microphone array. As the microphone array detects sounds,controller 1025 may populate an audio data set with the information. Inembodiments in which augmented-reality system 1000 includes an inertialmeasurement unit, controller 1025 may compute all inertial and spatialcalculations from the IMU located on eyewear device 1002. A connectormay convey information between augmented-reality system 1000 andneckband 1005 and between augmented-reality system 1000 and controller1025. The information may be in the form of optical data, electricaldata, wireless data, or any other transmittable data form. Moving theprocessing of information generated by augmented-reality system 1000 toneckband 1005 may reduce weight and heat in eyewear device 1002, makingit more comfortable to the user.

Power source 1035 in neckband 1005 may provide power to eyewear device1002 and/or to neckband 1005. Power source 1035 may include, withoutlimitation, lithium ion batteries, lithium-polymer batteries, primarylithium batteries, alkaline batteries, or any other form of powerstorage. In some cases, power source 1035 may be a wired power source.Including power source 1035 on neckband 1005 instead of on eyeweardevice 1002 may help better distribute the weight and heat generated bypower source 1035.

As noted, some artificial reality systems may, instead of blending anartificial reality with actual reality, substantially replace one ormore of a user's sensory perceptions of the real world with a virtualexperience. One example of this type of system is a head-worn displaysystem, such as virtual-reality system 1100 in FIG. 11, that mostly orcompletely covers a user's field of view. Virtual-reality system 1100may include a front rigid body 1102 and a band 1104 shaped to fit arounda user's head. Virtual-reality system 1100 may also include output audiotransducers 1106(A) and 1106(B). Furthermore, while not shown in FIG.11, front rigid body 1102 may include one or more electronic elements,including one or more electronic displays, one or more inertialmeasurement units (IMUS), one or more tracking emitters or detectors,and/or any other suitable device or system for creating an artificialreality experience.

Artificial reality systems may include a variety of types of visualfeedback mechanisms. For example, display devices in augmented-realitysystem 1100 and/or virtual-reality system 1100 may include one or moreliquid crystal displays (LCDs), light emitting diode (LED) displays,organic LED (OLED) displays, and/or any other suitable type of displayscreen. Artificial reality systems may include a single display screenfor both eyes or may provide a display screen for each eye, which mayallow for additional flexibility for varifocal adjustments or forcorrecting a user's refractive error. Some artificial reality systemsmay also include optical subsystems having one or more lenses (e.g.,conventional concave or convex lenses, Fresnel lenses, adjustable liquidlenses, etc.) through which a user may view a display screen.

In addition to or instead of using display screens, some artificialreality systems may include one or more projection systems. For example,display devices in augmented-reality system 1000 and/or virtual-realitysystem 1100 may include micro-LED projectors that project light (using,e.g., a waveguide) into display devices, such as clear combiner lensesthat allow ambient light to pass through. The display devices mayrefract the projected light toward a user's pupil and may enable a userto simultaneously view both artificial reality content and the realworld. Artificial reality systems may also be configured with any othersuitable type or form of image projection system.

Artificial reality systems may also include various types of computervision components and subsystems. For example, augmented-reality system900, augmented-reality system 1000, and/or virtual-reality system 1100may include one or more optical sensors, such as two-dimensional (2D) orthree-dimensional (3D) cameras, time-of-flight depth sensors,single-beam or sweeping laser rangefinders, 3D LiDAR sensors, and/or anyother suitable type or form of optical sensor. An artificial realitysystem may process data from one or more of these sensors to identify alocation of a user, to map the real world, to provide a user withcontext about real-world surroundings, and/or to perform a variety ofother functions.

Artificial reality systems may also include one or more input and/oroutput audio transducers. In the examples shown in FIGS. 9 and 11,output audio transducers 908(A), 908(B), 1106(A), and 1106(B) mayinclude voice coil speakers, ribbon speakers, electrostatic speakers,piezoelectric speakers, bone conduction transducers, cartilageconduction transducers, and/or any other suitable type or form of audiotransducer. Similarly, input audio transducers 910 may include condensermicrophones, dynamic microphones, ribbon microphones, and/or any othertype or form of input transducer. In some embodiments, a singletransducer may be used for both audio input and audio output.

While not shown in FIGS. 9-11, artificial reality systems may includetactile (i.e., haptic) feedback systems, which may be incorporated intoheadwear, gloves, body suits, handheld controllers, environmentaldevices (e.g., chairs, floormats, etc.), and/or any other type of deviceor system. Haptic feedback systems may provide various types ofcutaneous feedback, including vibration, force, traction, texture,and/or temperature. Haptic feedback systems may also provide varioustypes of kinesthetic feedback, such as motion and compliance. Hapticfeedback may be implemented using motors, piezoelectric actuators,fluidic systems, and/or a variety of other types of feedback mechanisms.Haptic feedback systems may be implemented independent of otherartificial reality devices, within other artificial reality devices,and/or in conjunction with other artificial reality devices.

By providing haptic sensations, audible content, and/or visual content,artificial reality systems may create an entire virtual experience orenhance a user's real-world experience in a variety of contexts andenvironments. For instance, artificial reality systems may assist orextend a user's perception, memory, or cognition within a particularenvironment. Some systems may enhance a user's interactions with otherpeople in the real world or may enable more immersive interactions withother people in a virtual world. Artificial reality systems may also beused for educational purposes (e.g., for teaching or training inschools, hospitals, government organizations, military organizations,business enterprises, etc.), entertainment purposes (e.g., for playingvideo games, listening to music, watching video content, etc.), and/orfor accessibility purposes (e.g., as hearing aids, visuals aids, etc.).The embodiments disclosed herein may enable or enhance a user'sartificial reality experience in one or more of these contexts andenvironments and/or in other contexts and environments.

In some examples, the virtual reality systems described and/orillustrated herein, including the associated OLED or LED displaysystems, may be implemented using any type or form of computing deviceor system capable of executing computer-readable instructions. In theirmost basic configuration, these device(s) may each include at least onememory device and at least one physical processor.

In some examples, the term “memory device” generally refers to any typeor form of volatile or non-volatile storage device or medium capable ofstoring data and/or computer-readable instructions. In one example, amemory device may store, load, and/or maintain one or more of themodules described herein. Examples of memory devices include, withoutlimitation, Random Access Memory (RAM), Read Only Memory (ROM), flashmemory, Hard Disk Drives (HDDs), Solid-State Drives (SSDs), optical diskdrives, caches, variations or combinations of one or more of the same,or any other suitable storage memory.

In some embodiments, the term “computer-readable medium” generallyrefers to any form of device, carrier, or medium capable of storing orcarrying computer-readable instructions. Examples of computer-readablemedia include, without limitation, transmission-type media, such ascarrier waves, and non-transitory-type media, such as magnetic-storagemedia (e.g., hard disk drives, tape drives, and floppy disks),optical-storage media (e.g., Compact Disks (CDs), Digital Video Disks(DVDs), and BLU-RAY disks), electronic-storage media (e.g., solid-statedrives and flash media), and other distribution systems.

In some examples, the term “physical processor,” “processing device,” or“controller” generally refers to any type or form ofhardware-implemented processing unit capable of interpreting and/orexecuting computer-readable instructions. In one example, a physicalprocessor may access and/or modify one or more modules stored in theabove-described memory device. Examples of physical processors include,without limitation, microprocessors, microcontrollers, image processors,Central Processing Units (CPUs), Field-Programmable Gate Arrays (FPGAs)that implement softcore processors, Application-Specific IntegratedCircuits (ASICs), portions of one or more of the same, variations orcombinations of one or more of the same, or any other suitable physicalprocessor.

In some examples, computer-executable instructions contained withinmodules may perform one or more of the steps, processes, and/orprocedures described and/or illustrated herein. These modules mayrepresent portions of a single module or application. In addition, incertain embodiments one or more of these modules may represent one ormore software applications or programs that, when executed by acomputing device, may cause the computing device to perform one or moretasks. For example, one or more of the modules described and/orillustrated herein may represent modules stored and configured to run onone or more of the devices or systems described and/or illustratedherein. One or more of these modules may also represent all or portionsof one or more special-purpose devices configured to perform one or moretasks.

In addition, one or more of the modules described herein may transformdata, physical devices, and/or representations of physical devices fromone form to another. Additionally, or alternatively, one or more of themodules recited herein may transform a processor, volatile memory,non-volatile memory, and/or any other portion of a physical computingdevice from one form to another by executing on the computing device,storing data on the computing device, and/or otherwise interacting withthe computing device.

The process parameters and sequence of the steps described and/orillustrated herein are given by way of example only and can be varied asdesired. For example, while the steps illustrated and/or describedherein may be shown or discussed in a particular order, these steps donot necessarily need to be performed in the order illustrated ordiscussed. The various exemplary methods described and/or illustratedherein may also omit one or more of the steps described or illustratedherein or include additional steps in addition to those disclosed.

The preceding description has been provided to enable others skilled inthe art to best utilize various aspects of the exemplary embodimentsdisclosed herein. This exemplary description is not intended to beexhaustive or to be limited to any precise form disclosed. Manymodifications and variations are possible without departing from thespirit and scope of the instant disclosure. The embodiments disclosedherein should be considered in all respects illustrative and notrestrictive. Reference should be made to the appended claims and theirequivalents in determining the scope of the instant disclosure.

Unless otherwise noted, the terms “connected to” and “coupled to” (andtheir derivatives), as used in the specification and claims, are to beconstrued as permitting both direct and indirect (i.e., via otherelements or components) connection. In addition, the terms “a” or “an,”as used in the specification and claims, are to be construed as meaning“at least one of.” Finally, for ease of use, the terms “including” and“having” (and their derivatives), as used in the specification andclaims, are interchangeable with and have the same meaning as the word“comprising.”

What is claimed is:
 1. A display system comprising: a display elementhaving an LED-containing display active area disposed over a siliconbackplane; a discrete display driver integrated circuit (DDIC) that isformed separately from the display element, wherein the DDIC is attachedto the display element and is electrically connected with the displayactive area; and a multiplexer disposed between the display element andthe discrete display driver integrated circuit, wherein a gate linedriving circuit is incorporated into the silicon backplane of thedisplay element, and wherein a data line driving circuit is incorporatedinto the DDIC.
 2. The display system of claim 1, wherein the displayactive area comprises a micro-OLED.
 3. The display system of claim 1,wherein the silicon backplane comprises single crystal silicon.
 4. Thedisplay system of claim 1, wherein the display driver integrated circuitis disposed on a flexible substrate.
 5. The display system of claim 1,wherein the display active area is electrically connected to the displaydriver integrated circuit via a wire bond.
 6. The display system ofclaim 1, wherein the display driver integrated circuit comprises asource driver.
 7. A device comprising: a display element having adisplay active area disposed over a single crystal semiconductorbackplane; a discrete display driver integrated circuit (DDIC) that isformed separately from the display element and that is bonded to thedisplay element; and a multiplexer disposed between the display elementand the discrete display driver integrated circuit, wherein a gate linedriving circuit is incorporated into the silicon backplane of thedisplay element, and wherein a data line driving circuit is incorporatedinto the DDIC.
 8. The device of claim 7, further comprising a pluralityof pixel transistors disposed over the backplane.
 9. The device of claim7, wherein the display active area comprises a micro-OLED and thedisplay driver integrated circuit comprises a source driver.
 10. Thedevice of claim 7, wherein the semiconductor backplane comprises singlecrystal silicon.